Pneumatic tire and method of fabricating same



Feb. 21, 1933. R. c. MURPHY A PNEUMTIC TIRE AND METHOD OF FABRICATING SAME Filed April 22, 1929 Patented Feb. 21, 1933 PATENT formes ROY C. MURPHY, F GRAND RAPIDS, MICHIGAN PNEUMATIC TIRE AND METHOD OF FABRIGATING SAME Application filed April 22,

The invention relates to a pneumatitc tire and method of fabricating same, and has to do particularly with .a novel4 manner of building up the plies of cord fabric preparatory to shaping and vulcanizing the tire casing.

In building upthe plies of cord fabric in the fabrication of pneumatic tires, it is customary to first windl two plies of cord fabric around a fiat or semi-fiat form. The beads are then set in having been first covered with a fiipper strip. After the edges of the first and second plies have been turned up over the beads, the additional plies are then laid on ytop of the first plies and their edges turned down over the bead and trimmed off. This is 'the standard method of forming the plies of cord fabric, but other attempts have been made to form and build up the plies 2 in different ways, one of which includes the idea of placing plies of extra width one on top of the other and then folding them over so that the circumferential edges meet or overlap atthe center of the tire. This latter form has proven very objectionable because,

in addition to unbalancing and stidening the tire casing, the joint is positioned at the point of greatestflexing and thus requires a gum strip to prevent breaking apart.

The present invention contemplates Aa novel and extremely simple method of initially building up thepfabric to form a casing in that the strips of cord fabricr are cut approximately double the standard width and folded over one upon the other, whereby to completely eliminate flippers and gum strips. Each bead is surrounded by at least one continuous layer of cord fabric and the edges of each layer of fabric terminate at 'V840 the beads. This'method of fabricating or building up the casing presents a final article which retains the beneficial points of the-standard casing now produced but which is much cheaper in assembly, eliminates various operations and material, and presents a very efficient article.

In they drawing: Y Fig. l is a diagrammatic view illustrating i the first 'step in the preferred form of my process. f

192s. serialv Np. 356,906.y Y

Fig. 2 is a diagrammatic sectional view illustrating the second step in the process wherein the opposite ends of the two layers of fabric are folded over to completely en, close the beads and to terminate at points T5' adjacent the opposite beads.V`r f Fig. Sis a diagrammatic view of the first step in a modified form yof my novel invention wherein the beads are enclosed by sepa rate'folded strips of fabric prior to assembly. 6

Fig. is a view illustrating the method of assembling and joining the separate strip shown in Fig. 3. l

The present invention relates to the for* mationrand building up the cord fabric base A ofthe casing, and while I have diagrammatically illustrated my inventionby showmg .the steps of building up the layers of fabric on a fiat form, it will be understoodthat such layers may bey built up on various Y shapes and sizes of forms. In the drawing I have not shown the band or drum, as any standard article may be used on which to build or wind the fabric, but instead I.

have merely diagrammatically illustrated the steps of forming, positioning, and assembhng the fabric strips to build up the tire base or carcass.

Instead of cutting the strips of fabric to the required width of the base, Ipreferably take two or more strips offabric 1 and 2 which'are approximately twice the width of the base or, in other words, twice the width of the standard layer of cord fabric. 85 These double width layers of fabric are then vplaced or wound on the form so that onehalf of each layer overlaps the other, as best shown in Fig. l. l

The halves of each strip which are first'go Wound or placed on the form may be designated 3 and 4 and the remaining half of each strip designated 5 and 6, respectively. While the halves 3 and if are being placed one upon the other, the other halves 5 and 95 A6 may be supported as shown in any suitable manner. Having once folded over the halves 3 and t the wires forming the beads 7 and 8 are next preferably wound directly on the carcass bead and at points adjacent 10 shown in Fig. 1, the other halves 5 and 6 of the two layers of fabric are` thenfolded v over whereby the half 5 of the one layer is folded completely around the bead 8 and terminates ad'acent the bead 7 and the half l5 6 folds completely around the bead 7 and .terminates adjacent the bead 8. The ends of each strip 1 and 2, are of course, folded faround the beads, as shown, whereby the base`or carcass is then ready for final yforming and the standard successive steps of expansion and vulcanizatibn. .Y

In Fi 3 and 4k I have shown a slightly modifie form of assembling my novel :fabric structure. In this modification onl one Widthyof .fabric is handled at a time,t at is, each strip of fabric is of double width the same as that used in the preferred form, as Yshown in Figsl and 2, but first folded over a single bead 9 to form two plies of fabric 10 and 11. Any number of these separate individual strips, such as shown at A in 3, may be'forme'd, and by merely reversing one of these strips as shown at B, it will be obvious that two alternately positioned strips or units A and B may be then assembled and pressed together to form a lfour-ply carcass or base, as shown in Fig. v4. Having ressed or built'up the two separate strips o fabric A and B, the ends of each strip are pressed or folded around the beads as shown at 12 and 13 in Fig. 4, preparatory t0 the final forming of the casing in the usual manner.

It will then be seen that I have provided an improved and extremely simplermethod of assembling a tire base or carcass whereby some of the cutting operations are reduced in half and theoperator is enabled to wind the bead on the carcassat the time of as- Sembly. This not only makes for an improved andl more simple bead design,but also rovides a casing which is well balanc In both forms of my invention, as shown, one of the most important features is the folding over of a double width of fabric over a bead so that each bead is comllely enclosed b a continuous length of bric, and where y all joints are made at the opposite bead. Thus, -in addition to completely eliminating the use-of a flipper strip or bead cover, I have also provided a base wherein the fabric layers are kuniformV and contiguous from bead to bead,kthe ends -of each ,double width strip .terminatin in 65 every instance adjacent opposite beads w ich is the logical point to terminate the circumferential joints or edges of the strips of fabric.

It will be understood that any number of plies of fabric may be added according to 7 the type of the casing being formed, the circumferential edges of each added stri whether single or double, being preferably wound or placed so as to terminate adjacent the beads.

What I claim is:

1. The steps in the forming of a tire casing which comprise, the placing of a plurality of strips of cord fabric on a form, each strip of fabric being substantiall twice the 80 effective width of the form, ap ying beads and folding over each strip of abric where'- by each bead `will be itioned circumferentially ad 'acent each outer edge of the form and centra ly of a folded over stri of fabric. 85

2. The steps in the forming o a tire casing which comprise, the placingv of a plurality of 'strips of cord fabric on a form, each strip of fabric beii substantially twice the effective width of t e form, ap lying beads ,5?0 and folding over each stri lof abric whereby each bead will be positionedcircumferentially adjacent each outer edge of the form and centrally .of a folded over strip of fabric, the layers of fabric between the beads .7.95 being uniform and continuous from beadto bead and the ends of each folded over strip of fabric terminating adjacent the sides of the casing. i

3. The steps` in the forming of a tire casing C500 which comprise, cutting strips of cord fabric so as to be substantially double the width of the carcass to be formed, applying substantially half of each strip to a form in such a manner that the circumferential vcenter of 05 each strip is adjacent one edge of the effective surface of the form, winding a bead on the form at a point adjacent said circumferential center of each strip and successively folding over the remaining half of each d10 strip to completethe four-ply base of the tire carcass.

4. The steps in the forming of aV tire casing which comprise, cuttin strips of cord fabric so as to be substantlally double the m5 width of the carcass to be formed, a plying substantially half of each strip to a germ in such a manner that the circumferential center of each stripfis adjacent one edge of the effective surface of the form, winding bead 5.120 wire on the form to form a bead at a point adjacent said circumferentialcenter of each strip and folding over the remaining half of each strip to complete the four-ply base m yof the tire carcass.

5. The steps in the forming of a tire casing which comprise, cutting strips of cord `fabric so as to be substantially double the width of the carcass to be formed, ap lying one half of each strip to a form in such a manner ,130

that the longitudinal center of each strip is adjacent one edge of the effective surface of the form, winding a bead on the form at a point adjacent said longitudinal center of each strip and folding over the remaining half of eachr strip to complete the four-ply base of the tire carcass, the layers of fabric between said beads being uniform and continuous and the free ends of each strip terminating and being folded over the opposite bead.

6. A base or carcass for a pneumatic tire casing, formed of a plurality of plies formed of sheets of fabric, and bead strips positioned circumferentially around each edge of the carcass, two of said sheets of fabric being substantially twice the width of the carcass and oppositely positioned, and each of said two strips being folded to enclose one of said beads and having both of its edges terminating adjacent the opposite bead.

7. A cord fabric base or carcass for pneumatic tires consisting of two beads positioned at opposite circumferential edges of said base, and a plurality of plies of cord fabric formed of sheets of fabric of a width approximately double the width of the carcass, said plies extending uniformly and continuous between said beads, each one of said beads being enclosed by at least one layer of fabric whereby to eliminate the use of a flipper strip.

8. The process of constructing a tire by the iat band method consisting in cutting two layers of fabric of a width substantially twice the width of a ply in the finished carcass, wrapping said layers about a drum,

half the width of one layer overlapping half the width of the other to form a band having two ply thicknesses in the center and single ply thicknesses on each side of substantially the same width as the center two ply thickness, applying beads at each edge of the two ply portions of the layers, and folding the wings of the layers over the beads from opposite directions whereby four plies of fabric are obtained for the entire width of the tire, only one thickness of fabric enclosing the bead at each side of the tire.

In testimony whereof I affix my signature.

ROY C. MURPHY. 

